[thomasmg]

Why do you think so? The code example shows that you can do RLE (run length encoding) without noise / additional space. I'm pretty sure you can do zip as well. It would just be very hard to implement, but it wouldn't necessarily require that the output contains noise.

[1] https://topps.diku.dk/pirc/?id=janusP

[evanb]

Hmm. As a physicist my intuition is that information-preserving transformations are unitary (unitary transformations are 1-to-1). If a compression algorithm is going to yield a bit string (the zip file, for example) shorter than the original it can't be 1-to-1. So it must yield the zip file and some other stuff to make up for the space saved by the compression.